Abstract: Contents of neutral aroma constituents and alkaloids were compared in 5 types of tobacco (flue-cured, burley, Oriental, Maryland and sun-cured) from Sichuan Province. The results showed that total contents of neutral aroma components in flue-cured tobacco and sun-cured of Wanyuan were higher than other types of tobacco and most of indices of neutral aroma showed significant difference. Except neophytadiene other groups of neutral aroma in sun-cured of Wanyuan had the higest levels and the contents of products degraded by carotene were significantly higher than other kinds of tobacco. The contents of nicotine and nornicotine in 5 types of tobacco were largely different while the anabasine and anatabine showed no significant changes. The content of nornicotine and the nicotine conversion rate in burley were higher than other types obviously and that could be bad for the inner quality of tobacco.